If you are wondering about human-derived cell lines, then check out BioGPS.

You can search for your gene of interest, then you'll get a screen showing data for human tissues. Towards the top, you can select the DataSet you wish to view. Choose NCI60 and you will get a profile showing relative expression levels of the gene in a variety of human cell lines - including HeLa, OVCAR, 293T to name a few.....